U.S. patent number 10,832,606 [Application Number 16/198,308] was granted by the patent office on 2020-11-10 for display driving device.
This patent grant is currently assigned to Silicon Works Co., Ltd.. The grantee listed for this patent is SILICON WORKS CO., LTD.. Invention is credited to Beom Rak Choi, Young Bok Kim.
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United States Patent |
10,832,606 |
Kim , et al. |
November 10, 2020 |
Display driving device
Abstract
Disclosed is a display driving device capable of determining
whether a display panel is shorted, based on a voltage level shared
by data lines. The display driving device may include: a data
driving unit configured to provide source driving signals to data
lines of a display panel in a data output period, and control the
data lines to share charges in a charge sharing period; and a short
monitoring unit configured to detect a voltage level shared in the
charge sharing period, and compare the voltage level with a
reference voltage that varies according to the voltage level to
monitor whether the display panel is shorted.
Inventors: |
Kim; Young Bok (Daejeon,
KR), Choi; Beom Rak (Daejeon, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
SILICON WORKS CO., LTD. |
Daejeon-si |
N/A |
KR |
|
|
Assignee: |
Silicon Works Co., Ltd.
(Daejeon-si, KR)
|
Family
ID: |
1000005174828 |
Appl.
No.: |
16/198,308 |
Filed: |
November 21, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190156716 A1 |
May 23, 2019 |
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Foreign Application Priority Data
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Nov 23, 2017 [KR] |
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10-2017-0157025 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G09G
3/20 (20130101); G09G 3/006 (20130101); G09G
2330/045 (20130101); G09G 2330/12 (20130101); G09G
3/3685 (20130101); G09G 3/3275 (20130101) |
Current International
Class: |
G09G
3/00 (20060101); G09G 3/36 (20060101); G09G
3/20 (20060101); G09G 3/3275 (20160101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10-2017-0002098 |
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Jan 2017 |
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KR |
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10-2017-0099421 |
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Sep 2017 |
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KR |
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10-1816256 |
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Jan 2018 |
|
KR |
|
Primary Examiner: Patel; Nitin
Attorney, Agent or Firm: Polsinelli PC
Claims
What is claimed is:
1. A display driving device comprising: a data driving unit
configured to provide source driving signals corresponding to an
image data to data lines of a display panel in a data output
period, and control switch circuits to share charges of the data
lines in a charge sharing period; a switch configured to detect a
voltage level shared of the data lines in the charge sharing
period; a comparator configured to compare the voltage level with a
reference voltage and output a detection signal corresponding to
the comparison result; and a controller configured to determine
whether a short of the data lines according to the detection
signal, wherein the reference voltage is set to vary according to
the voltage level at which the source driving signals corresponding
to the image data are shared.
2. The display driving device of claim 1, wherein the reference
voltage is set to a lower level than the shared voltage level.
3. The display driving device of claim 1, wherein the controller
determines that a short path is present in the display panel, when
the shared voltage level is lower than the reference voltage.
4. The display driving device of claim 3, wherein the controller
powers down the data driving unit, when determining that a short
path is present.
5. The display driving device of claim 1, wherein the switch, the
comparator and the controller are configured for each group
including a predetermined number of data lines.
6. The display driving device of claim 1, wherein the controller
outputs a control signal for powering down the data driving unit,
when determining that a short path is present in the display
panel.
7. A display driving device comprising: a first switch circuit
configured to provide source driving signals corresponding to an
image data to data lines of a display panel in a data output
period; a second switch circuit configured to connect the data
lines to share charges in a charge sharing period; a switch
configured to transfer a voltage level of the data lines when the
charges of the data lines are shared through the second switch
circuit; a comparator configured to compare the voltage level with
a reference voltage and output a detection signal corresponding to
the comparison result; and a controller configured to determine
whether a short of the data lines according to the detection
signal, wherein the reference voltage is set to vary according to
the voltage level at which the source driving signals corresponding
to the image data are shared.
8. The display driving device of claim 7, wherein the switch is set
to be turned on after the charges of all of the data lines are
shared by the second switch circuit.
9. The display driving device of claim 7, wherein the reference
voltage is set to a lower level than the shared voltage level.
10. The display driving device of claim 7, wherein the controller
determines that a short path is present in the display panel, when
the shared voltage level is lower than the reference voltage.
11. The display driving device of claim 7, wherein the switch, the
comparator and the controller are configured for each group
including a predetermined number of data lines.
12. A display driving device comprising: a data driving unit
configured to provide source driving signals corresponding to an
image data to data lines of a display panel in a data output period
and control switch circuits to share charges of the data lines in a
charge sharing period; a switch configured to transfer a voltage
level which is shared by the data lines through the data driving
unit; a comparator configured to compare the voltage level with a
reference voltage, and output a detection signal corresponding to
the comparison result; and a controller configured to determine
whether a short of the data lines, according to the detection
signal of the comparator, and output a control signal for powering
down the data driving unit, when determining that a short path is
present in the display panel, wherein the reference voltage is set
to vary according to the voltage level at which the source driving
signals corresponding to the image data are shared.
13. The display driving device of claim 12, wherein the reference
voltage is set to a lower level than the shared voltage level.
14. The display driving device of claim 12, wherein when the
detection signal indicating that the voltage level is lower than
the reference voltage is inputted, the controller determines that a
short path is present in the display panel, and enables the control
signal for powering down the data driving unit.
Description
BACKGROUND
1. Technical Field
The present disclosure relates to a display device, and more
particularly, to a display driving device capable of monitoring
whether a display panel is shorted.
2. Related Art
A display device includes a display panel, a display driving device
and a timing controller. The display driving device converts
digital image data provided from the timing controller into a
source driving signal, and provides the source driving signal to
the display panel.
The display driving device includes a digital-analog converter
(DAC) for converting the digital image data into the source driving
signal and an output circuit for outputting the source driving
signal to data lines of the display panel. Such a display driving
device performs an operation of providing the source driving signal
to the data lines of the display panel or controlling the data
lines to share charges, according to a source output enable
signal.
When a physical short circuit occurs between the data lines and
adjacent lines in the display panel, a short current may flow into
the display panel. When the surface temperature of the display
panel rapidly rises due to the short current, a safety problem may
occur.
Therefore, there is a demand for a technique for solving a safety
problem which may occur due to a short current.
SUMMARY
Various embodiments are directed to a display driving device
capable of monitoring whether a display panel is shorted.
In an embodiment, a display driving device may include: a data
driving unit configured to provide source driving signals to data
lines of a display panel in a data output period, and control the
data lines to share charges in a charge sharing period; and a short
monitoring unit configured to detect a voltage level shared in the
charge sharing period, and compare the voltage level with a
reference voltage that varies according to the voltage level to
monitor whether the display panel is shorted.
In an embodiment, a display driving device may include: a first
switch circuit configured to control data lines of a display panel
to share charges in a charge sharing period; a second switch
circuit configured to transfer a shared voltage level when the
charges of the data lines are shared through the first switch
circuit; and a short monitoring unit configured to monitor whether
a display panel is shorted, by comparing the voltage level detected
by the second switch circuit with a reference voltage that varies
according to the voltage level.
In an embodiment, a display driving device may include: a data
driving unit configured to control data lines of a display panel to
share charges in a charge sharing period; a switch configured to
transfer a voltage level which is shared by the data lines through
the data driving unit; a comparator configured to compare the
voltage level with a reference voltage that varies according to the
voltage level, and output a detection signal corresponding to the
comparison result; and a controller configured to determine whether
a short path is present in the display panel, according to the
detection signal of the comparator, and output a control signal for
powering down the data driving unit, when determining that a short
path is present in the display panel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram for describing a display driving device
in accordance with an embodiment of the present invention.
FIG. 2 is a waveform diagram for describing operations of switch
circuits illustrated in FIG. 1.
FIG. 3 is a waveform diagram illustrating a data output when a
ground voltage short circuit occurs in a display panel of FIG.
1.
DETAILED DESCRIPTION
Hereafter, embodiments of the present invention will be described
in detail with reference to the accompanying drawings. The terms
used in this specification and claims are not limited to typical
dictionary definitions, but should be interpreted as meanings and
concepts which coincide with the technical idea of the present
invention.
Embodiments described in this specification and configurations
illustrated in the drawings are preferred embodiments of the
present invention, and do not represent the entire technical idea
of the present invention. Thus, various equivalents and
modifications capable of replacing the embodiments and
configurations may be provided at the time that the present
application is filed.
FIG. 1 is a block diagram for describing a display driving device
100 in accordance with an embodiment of the present invention.
Referring to FIG. 1, the display device includes a display panel
200 and a display driving device 100.
The display panel 200 may include a liquid crystal panel, an OLED
(Organic Light Emitting Diode) panel and the like. The display
panel 200 includes data lines, gate lines, power supply lines and
sensing lines formed therein, and pixels may be formed in a matrix
shape at the respective intersections between the data lines and
the gate lines.
The display driving device 100 performs a driving operation of
providing a source driving signal to the display panel in a data
output period, and performs a charge sharing operation of
controlling the data lines of the display panel to share charges in
a charge sharing period.
The display driving device 100 receives digital image data from a
timing controller (not illustrated) in the data output period, and
provides source driving signals S1 to Sn corresponding to the
digital image data to the data lines of the display panel 200.
The display driving device 100 controls internal switches in order
for the data lines of the display panel 200 to charge shares in the
charge sharing period. When a physical short circuit occurs between
the data lines and adjacent lines in the display panel 200, a short
current may flow into the display panel 200. The display driving
device 100 in accordance with the embodiment of the present
invention may monitor whether the display panel 200 is shorted,
using a voltage level shared by the data lines in the charge
sharing period.
The display driving device includes a data driving unit 10 and a
short monitoring unit 20.
Referring to FIG. 1, the data driving unit 10 includes a buffer
circuit 12, a switch circuit 14 and a switch circuit 16. The buffer
circuit 12 buffers the source driving signals S1 to Sn
corresponding to the digital image data, the switch circuit 14
transfers the source driving signals S1 to Sn to the data lines of
the display panel 200, and the switch circuit 16 controls the data
lines of the display panel 200 to share their charges.
The switch circuit 14 is turned on to transfer the source driving
signals S1 to Sn to the data lines in the data output period, and
the switch circuit 16 is turned on to electrically connect the data
lines to share charges in the data sharing period.
Although not illustrated in FIG. 1, the data driving unit 10 may
include a latch circuit for latching the digital image data
provided from the timing controller and a digital-analog converter
(DAC) for converting the digital analog data into the source
driving signals S1 to Sn as analog signals.
The short monitoring unit 20 may detect a voltage level shared
through the turn-on of the switch circuit 16 in the charge sharing
period, and compare the voltage level with a reference voltage that
varies according to the voltage level to monitor whether the
display panel is shorted.
The reference voltage VREF may be varied according to the voltage
level shared in the charge sharing period, and set to a lower level
than the shared voltage level. For example, gamma voltages for
converting the digital image data into the source driving signals
may be used as the reference voltage VREF. Alternatively, reference
voltages generated through a separate reference voltage generator
(not illustrated) may be used as the reference voltage VREF.
The short monitoring unit 20 includes a switch 22, a comparator 24
and a controller 26.
Referring to FIG. 1, the switch 22 is electrically coupled to the
switch circuit 16 for controlling the data lines to share charges,
and the switch circuit 16 transfers the charges shared by the data
lines to the comparator 24. The switch circuit 16 may have a preset
turn-on time enough for all of the data lines to share charges, and
the switch 22 may be turned on after the time required for all of
the data lines to share charges through the switch circuit 16.
The comparator 24 compares the voltage level transferred by the
switch 22 to the set reference voltage VREF, and outputs a
detection signal corresponding to the comparison result. When the
voltage level is higher or lower than the reference voltage VREF,
the comparator 24 outputs a high or low logic signal corresponding
to the voltage level. The logic level of the detection signal
outputted from the comparator 24 may be changed according to the
design of the comparator 24.
When a short path is present in the display panel 200, the voltage
levels of the data lines may be lower than the reference voltage
VREF. That is, when a short path is present in the display panel
200, the comparator 24 outputs a set high or low logical
signal.
The controller 26 determines whether a short path is present in the
display panel 200, according to the logic level of the detection
signal DS outputted from the comparator 24. When the detection
signal DS is inputted as a high or low logic signal, the controller
26 determines that a short path is present in the display panel
200, and enables and outputs a control signal CS for powering down
the data driving unit 10 which provides the source driving signal
to the display panel.
The control signal CS may be used to power down the DAC for
converting the digital image data into the source driving signals
using gamma voltages in the data driving unit 10 or an output
buffer for buffering and outputting the source driving signals.
Alternatively, the control signal CS may be used to power down the
display driving device 100 including the data driving unit 10.
For example, when the data driving unit 10 drives image data
corresponding to black in the data output period, the voltage
levels of the data lines may converge to a half supply voltage (1/2
VDD) in the charge sharing period. When a short path is present in
the display panel 200, the voltage levels of the data lines may be
lower than the half supply voltage (1/2 VDD). When the voltage
level is detected as a lower level than the set reference voltage,
the short monitoring unit 20 may determine that a short path is
present in the display panel 200.
In order to improve the detection accuracy of the shared voltage
level, the data lines of the display panel 200 may be divided into
groups each including a predetermined number of data lines, and the
short monitoring unit 20 may be provided for each of the groups to
monitor the voltage level.
FIG. 2 is a waveform diagram for describing operations of the
switch circuits illustrated in FIG. 1.
Referring to FIGS. 1 and 2, the switch circuits 14 and 16 may be
turned on or off according to the logic level of a source output
enable signal SOE. For example, suppose that the source output
enable signal SOE is inputted at a logic low level in the data
output period, and inputted at a logic high level in the charge
sharing period. However, the present embodiment is not limited
thereto.
When the source output enable signal SOE is inputted at a logic low
level in the data output period, the switch circuit 14 is turned
on, and the switch circuit 16 is turned off. Then, the source
driving signals S1 to Sn corresponding to the digital image data
are provided to the display panel 200.
When the source output enable signal SOE is inputted at a logic
high level in the charge sharing period, the switch circuit 14 is
turned off, and the switch circuit 16 is turned on. Then, charges
of all the data lines are shared. The short monitoring unit 20 may
be enabled in the charge sharing period. For example, the charge
sharing period may be set to a vertical blank period of the display
device. That is, the short monitoring unit 20 may be configured to
monitor whether the display panel is shorted, in the vertical bland
period.
The shared voltage level may correspond to a level at which the
source driving signals corresponding to the data image data
provided from the timing controller are shared, and the reference
voltage may be varied according to the shared voltage level, and
set to a lower level than the shared voltage level.
In the present embodiment, it is described that the source driving
signals are shared at the voltage level corresponding to the
digital image data provided from the timing controller. However,
the source driving signals may be shared at a voltage level
corresponding to set data in the charge sharing period. In this
case, the reference voltage may be set to a fixed value lower than
a voltage level corresponding to the set data.
FIG. 3 is a waveform diagram illustrating a data output when a
ground voltage short circuit occurs in the display panel of FIG.
1.
In FIG. 3, a dotted line represents a data output during a normal
operation, and a solid line represents a data output during an
abnormal operation. As illustrated in FIG. 3, when a ground voltage
short circuit occurs in the display panel, the data output becomes
lower than during the normal operation. In this way, by monitoring
the voltage levels of the data lines, it is possible determine
whether the display panel is shorted.
As described above, the display driving device in accordance with
the embodiment of the present invention may monitor the voltage
level shared in the charge sharing period, thereby determining
whether the display panel is shorted.
When determining that a short path is present in the display panel,
the display driving device may power down the data driving unit for
providing the source driving signals to the display panel, thereby
preventing a safety problem that the temperature of the display
panel rapidly rises due to a short current.
While various embodiments have been described above, it will be
understood to those skilled in the art that the embodiments
described are by way of example only. Accordingly, the disclosure
described herein should not be limited based on the described
embodiments.
* * * * *